Southern Beardless Tyrannulet
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| Camptostoma obsoletum (Temminck, 1824) |
The Southern Beardless Tyrannulet, Camptostoma obsoletum, is a small passerine bird in the tyrant flycatcher family. It breeds from Costa Rica through South America south to Paraguay, Bolivia, and Argentina. The race C. o. venezuelae occurs only in Trinidad and Venezuela, and differs in plumage tone from the nominate form.
This species is found in light forests, cultivation and gardens with trees. The domed nest is made of plant fibre or leaves with a side entrance. The nest is placed by a tree fork, usually near a wasp nest, which presumably provides some protection from predators. The typical clutch is two white eggs, which are marked with rufous and lilac mostly at the larger end. Incubation by the female is 14-15 days to hatching, with another 17 days to fledging.
The Southern Beardless Tyrannulet is 10.2 cm long, weighs 7.5g and often resembles a tiny Yellow-bellied Elaenia. The head is dark brown with an erectile crest and pale supercilium. The upperparts are grey-green becoming paler on the rump. The wings are brown with yellow feather-edging and two whitish wing bars. The tail is brown, the throat grey, the breast yellowish, and the abdomen yellow. The bill is pinkish.
Sexes are similar, and this species always appears brighter, especially with regard to the wing bars, than the closely related Northern Beardless Tyrannulet, C. imberbe, with which it was once considered conspecific. However, the two forms overlap without interbreeding in central Costa Rica.
Southern Beardless Tyrannulets are active birds, feeding in a vireo or warbler-like fashion on insects, spiders and berries. The call is a loud whistled TLEEE-tee-tee-tee. In courtship, the crests are raised, the tail flicked, and an excited mixture of the TLEE call and a churring pee-chrrr-pee-chrrr is given. This species will readily mob the Ferruginous Pygmy Owl.
[edit] References
- BirdLife International (2004). Camptostoma obsoletum. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern
- ffrench, Richard (1991). A Guide to the Birds of Trinidad and Tobago, 2nd edition, Comstock Publishing. ISBN 0-8014-9792-2.
- Hilty, Steven L (2003). Birds of Venezuela. London: Christopher Helm. ISBN 0-7136-6418-5.
- A guide to the birds of Costa Rica by Stiles and Skutch ISBN 0-8014-9600-4
